Coolant temperature controlling system for engine performance test

ABSTRACT

The present invention provides a coolant temperature control system for engine performance test, comprising an internal coolant circulation system, a heat exchange unit, a temperature monitoring and control unit, and an external coolant circulation system, wherein, the internal coolant circulation system and the external coolant circulation system are connected to the heat exchange unit respectively, and the internal coolant circulation system is connected to the engine; the temperature monitoring and control unit is connected to the internal coolant circulation system, the heat exchange unit, and the external coolant circulation system respectively, and the internal coolant circulation system is a closed internal circulation system. A vapor exhaust pipe connects the water channel in the engine cylinder head to an expansion water tank; a bypass pipe and a bypass valve are mounted to the water inlet and water outlet of the engine.

FIELD OF THE INVENTION

The present invention relates to an engine performance testing device,in particular to a coolant temperature control system for engineperformance test.

BACKGROUND OF THE INVENTION

A circulating water system is of great significance to ensure normaloperation of the engine in test. The conventional circulating watertemperature control method is an open circulation method (i.e., thecirculating water is driven by a water pump for the engine to flow outfrom the engine, exchanges heat and thereby is cooled in a radiator, andthen returns to the engine), which is to say, the coolant is driven by awater pump for the engine to flow out from the engine, exchanges heatand thereby is cooled in a radiator, and then returns to the engine, asshown in FIG. 1. In the implementation process of the embodiments of thepresent invention, the inventor has found that the method in the priorart has at least the following problems. Though the method can attainthe purpose of engine cooling control, it can't control the coolantpressure effectively; in addition, when the coolant temperature is nearthe 100° C. boiling point, a great deal of vapor will be produced in theengine and the coolant circulation loop, and can't be exhaustedeffectively. That condition is quite different to the actual conditionof an engine operating in the vehicle, and can't be used to study andverify the actual cooling capability for the engine comprehensively. Thetest result can't truly meet the actual demand for engine test. Forexample, the engine coolant temperature control device disclosed in theChinese Utility Model Patent No. 200620116208.0 titled as “EngineCoolant Temperature Control Device” has the above-mentioned problems.

SUMMARY OF THE INVENTION

The present invention provides a coolant temperature control system forengine performance test, to control the pressure of water flowinginto/out of the engine in test and simulate the operating condition ofthe engine in a vehicle.

To attain the above-mentioned object, in an embodiments according to thepresent invention provides a coolant temperature control system forengine performance test, comprising an internal coolant circulationsystem, a heat exchange unit, a temperature monitoring and control unit,and an external coolant circulation system, wherein, the internalcoolant circulation system and the external coolant circulation systemare connected to the heat exchange unit respectively, and the internalcoolant circulation system is connected to the engine; the temperaturemonitoring and control unit is connected to the internal coolantcirculation system, the heat exchange unit, and the external coolantcirculation system; wherein, the internal coolant circulation system isa closed internal circulation system provided with a pipeline forreducing the difference between water inlet pressure and water outletpressure of the internal coolant circulation system.

In the coolant temperature control system described above, the closedinternal circulation system comprises an engine water outlet pipe, anexpansion water tank, a heat exchange pipe, an engine water inlet pipe,and a bypass unit, which are connected in sequence, wherein, the bypassunit comprises a bypass pipe and a bypass valve, the bypass valve ismounted on the bypass pipe, and the bypass pipe communicates the enginewater inlet pipe with the engine water outlet pipe to reduce thedifference between inlet pressure and outlet pressure of the internalcoolant circulation system; the engine water outlet pipe is connected tothe water outlet of the engine; the engine water inlet pipe is connectedto the water inlet of the engine; the heat exchange pipe is connected tothe heat exchange unit.

In the coolant temperature control system described above, the closedinternal circulation system further comprises a vapor exhaust unit whichcomprises an extension pipe and a vapor exhaust pipe, wherein, one endof the extension pipe is connected to the top of the expansion watertank, and the other end of the extension pipe is provided with a valve;the vapor exhaust pipe connects a water channel in the cylinder head ofthe engine to the extension pipe.

In the coolant temperature control system described above, thetemperature monitoring and control system comprises a temperature sensorand an electric temperature control box that are connected to eachother, wherein, the temperature sensor is mounted on the engine wateroutlet pipe, and the electric temperature control box is connected tothe heat exchange unit and the external coolant circulation system.

In the coolant temperature control system described above, the heatexchange unit is a plate-type heat exchanger.

In the coolant temperature control system, the heat exchanger pipe isfurther provided with a manual bleed valve and an automatic bleed valve.

In the coolant temperature control system, the engine water inlet pipeis further provided with a water replenishing valve.

In the coolant temperature control system described above, a coolantfilter is further provided on the heat exchange pipe at the end near theexpansion water tank.

In the coolant temperature control system described above, a regulatingvalve is provided at the joint between the heat exchange pipe and theengine water inlet pipe.

In the coolant temperature control system described above, a valve isprovided at the joint between the engine water outlet pipe and theexpansion water tank, and a valve is provided at the joint between theheat exchange pipe and the engine water inlet pipe.

The beneficial efficacies of the present invention lie in: a vaporexhaust pipe is added to the existing coolant temperature controlsystem, and the vapor exhaust pipe connects the water channel in thecylinder head of the engine to an expansion water tank to ensure normalvapor exhaust of the circulating water channel in the engine; a bypasspipe and a bypass valve are mounted to the water inlet and water outletof the engine to compensate the water inlet pressure with the wateroutlet pressure, so as to further reduce the difference between waterinlet pressure and water outlet pressure and increase water inflow rateand water outflow rate; thus, the system provided in the presentinvention attain the purpose of simulating the actual operatingcondition of engine in the vehicle for the cooling water system in theengine test, can keep the engine operating stably at 100° C. boilingpoint, and can increase the water inlet pressure by 20-50 kPa in thetest.

Hereunder the present invention will be detailed in embodiments, withreference to the accompanying drawings; however, the present inventionis not limited to the embodiments and drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a schematic diagram of the coolant temperature control systemin the prior art;

FIG. 2 is a schematic diagram of the coolant temperature control systemaccording to an embodiment of the present invention;

FIG. 3 is a schematic diagram showing the working principle of thecoolant temperature control system according to an embodiment of thepresent invention;

FIG. 4 is a schematic diagram showing the structure of the coolanttemperature control system according to an embodiment of the presentinvention.

Wherein, the symbols in the drawings are:

1. Engine

-   11. Water outlet-   12. Water inlet-   13. Water channel in cylinder head

2. Internal coolant circulation system

-   20. Closed internal circulation system    -   201. Engine water outlet pipe        -   2011. Valve I    -   202. Engine water inlet pipe        -   2021. Valve II        -   2022. Water replenishing valve    -   203. Heat exchange pipe        -   2031. Automatic bleed valve        -   2032. Manual bleed valve        -   2033. Regulating valve        -   2034, 2035 Coolant filter    -   204. Bypass unit        -   2041. Bypass valve        -   2042. Bypass pipe    -   205. Vapor exhaust unit        -   2051. Valve        -   2052. Extension pipe        -   2053. Vapor exhaust pipe    -   207. Expansion water tank        -   2071. Pressure limiting valve        -   2072. Pressure meter-   21. Open internal circulation system

3. Heat exchange unit

-   31. Plate-type heat exchanger

4. Temperature monitoring and control unit

-   41. Temperature sensor-   42. Electric temperature control box

5. External coolant circulation system

DETAILED DESCRIPTION OF THE EMBODIMENTS

Hereunder the structure and working principle of the device provided inan embodiment of the present invention will be detailed, with referenceto the accompanying drawings.

The coolant described in the embodiment of the present invention can bewater or any other coolant; in the embodiment of the present invention,water or a coolant is employed in the internal circulation system, whilewater is employed in the external circulation system; however, thepresent invention is not limited to these. In the embodiment of thepresent invention, the external circulation system is a known techniquein the prior art, and therefore will not be detailed here. Hereunder theinternal circulation system in the embodiment of the present inventionwill be detailed.

In engine tests, test control has to be exercised often by simulatingthe actual operating condition of engine in a vehicle and applying avariety of complex test conditions. The control of circulating water forengine is of great significance in an engine test, and is a decisivefactor for normal test and operation of the engine. The conventionalcirculating water temperature control method is an open circulationmethod (i.e., the circulating water is driven by a water pump for theengine to flow out from the engine, exchanges heat and thereby is cooledin a radiator, and then returns to the engine). FIG. 1 is a schematicdiagram of the coolant temperature control system in the prior art. Asshown in FIG. 1, the internal coolant circulation system is an openinternal circulation system 21. Though the conventional method caneffectively control the circulating water temperature for the engine,the condition is quite different from the actual operating condition ofthe engine in a vehicle; in addition, the water inflow pressure can't becontrolled effectively, and the test result can't truly show the actualdemand for engine test. In the embodiment of the present invention, asimple coolant temperature control system, which can control the waterinflow pressure and outflow pressure of engine and simulate the actualoperating condition of engine in a vehicle, is designed, incorporatingdifferent test conditions for engine test. Please see FIGS. 2, 3, and 4,wherein, FIG. 2 is a schematic diagram of the coolant temperaturecontrol system provided in an embodiment of the present invention, FIG.3 is a schematic diagram showing the working principle of the coolanttemperature control system in an embodiment of the present invention,and FIG. 4 is a schematic diagram showing the structure of the coolanttemperature control system provided in an embodiment of the presentinvention. The coolant temperature control system for engine performancetest provided in the embodiment of the present invention comprises aninternal coolant circulation system 2, a heat exchange unit 3, atemperature monitoring and control unit 4, and an external coolantcirculation system 5, wherein, the internal coolant circulation system 2and the external coolant circulation system 5 are connected to the heatexchange unit 3 respectively; the internal coolant circulation system 2is connected to the engine 1; the temperature monitoring and controlunit 4 is connected to the internal coolant circulation system 2, theheat exchange unit 3, and the external coolant circulation system 5; theinternal coolant circulation system 2 is a closed internal circulationsystem 20, with a bypass unit 204 mounted between an engine water inletpipe 202 and an engine water outlet pipe 201, the bypass unit 204communicates with the engine water inlet pipe 202 and the engine wateroutlet pipe 201, so that the internal coolant circulation system for theengine forms a closed system, and the water inlet pressure iscompensated by the water outlet pressure via the bypass unit 204; thus,the difference between water inlet pressure and water outlet pressure isreduced, and water inflow rate and water outflow rate are increased. Inthe embodiment, the internal coolant circulation system 2 comprises anengine water outlet pipe 201, an expansion water tank 207, a heatexchange pipe 203, an engine water inlet pipe 202, and a bypass pipe2042 and a bypass valve 2041, which are connected in sequence, wherein,the engine water outlet pipe 201 is connected to the water outlet 11 ofthe engine 1, the engine water inlet pipe 202 is connected to the waterinlet 12 of the engine 1, the bypass valve 2041 is mounted on the bypasspipe 2042, the bypass pipe 2042 communicates with the engine water inletpipe 202 and the engine water outlet pipe 201, and the heat exchangepipe 203 is connected to the heat exchange unit 3. A water replenishingvalve 2022 is mounted on the engine water inlet pipe 202. If water forthe engine is used as the coolant, the water replenishing valve 2022 canbe opened when required, so that the engine water inlet pipe 202communicates with the external coolant circulation system 5 and therebythe closed internal circulation system 20 can be replenished with thecirculating water in the external coolant circulation system 5. Theengine water outlet pipe 201 connects the engine water outlet 11 to theexpansion water tank 207, and a valve I 2011 is mounted at the jointbetween the engine water outlet pipe 201 and the expansion water tank207; the heat exchange pipe 203 connects the expansion water tank 207 tothe engine water inlet pipe 202, and a valve II 2021 is mounted at thejoint between the heat exchange pipe 203 and the engine water inlet pipe202; a coolant filter 2034 is mounted on the heat exchange pipe 203 atan end near the expansion water tank 207; a regulating valve 2033 ismounted at the joint between the heat exchange pipe 203 and the enginewater inlet pipe 202, and the regulating valve 2033 is connected withthe engine water inlet pipe 202, the heat exchange pipe 203, and theheat exchange unit 3 respectively; a coolant filter 2035 is mounted onthe pipeline via which the regulating valve 2033 is connected to theexternal coolant circulation system 5, so as to filter the coolant thatflows from the external coolant circulation system 5 into the heatexchange unit 3; in this embodiment, the heat exchange unit 3 is aplate-type heat exchanger 31; an automatic bleed valve 2032 and a manualbleed valve 2031 are mounted on the pipeline via which the regulatingvalve 2033 is connected to the plate-type heat exchanger 31. The enginewater inlet pipe 202 is communicated with the engine water outlet pipe201 through the bypass pipe 2042 with the bypass valve 2041; the bypasspipe 2042 is arranged at the side near the heat exchange pipe 203, andthe compensatory pressure of water outflow for water inflow iscontrolled by regulating the valve opening of the bypass valve 2041, soas to reduce the difference between water inlet pressure and wateroutlet pressure. The closed internal circulation system 20 furthercomprises a vapor exhaust unit 205, which comprises an extension pipe2052 and an vapor exhaust pipe 2053, wherein, the extension pipe 2052 isconnected at one end thereof to the top of the expansion water tank 207and is provided with a valve 2051 on the terminal thereof, and the valve2051 is in normally closed state during normal operation; the vaporexhaust pipe 2053 connects the water channel 13 in the cylinder head ofthe engine 1 to the extension pipe 2052 on the expansion water tank 207in a way that the end of the vapor exhaust pipe 2053 connected to theextension pipe 2052 is higher than the other end of the vapor exhaustpipe 2053 connected to the water channel 13 in the cylinder head of theengine 1 and the vapor exhaust pipe 2053 is not in bent state. Vapor isproduced as the water temperature rises up during operation of theengine, and the vapor is exhausted through the vapor exhaust pipe 2053to the expansion water tank 207. Once a pressure meter 2072 detects thepressure in the expansion water tank 207 is higher than a set value, apressure limiting valve 2071 will be opened to regulate the pressure. Inthis embodiment, the heat exchange unit 3 is a plate-type heat exchanger31. The temperature monitoring and control system 4 comprises atemperature sensor 41 and an electric temperature control box 42 thatare connected to each other, wherein, the temperature sensor 41 ismounted at the engine water outlet 21, and is used to monitor thetemperature of the circulating coolant and transmit the temperaturesignal to the electric temperature control box 42; the temperaturecontrol box 42 are connected to the heat exchange unit 3, externalcoolant circulation system 5, and a control system (not shown),respectively.

In summary, in the embodiments of the present invention, a vapor exhaustpipe is added to the existing coolant temperature control system, andthe vapor exhaust pipe connects the water channel in the cylinder headof the engine to an expansion water tank to ensure normal vapor exhaustof the circulating water channel in the engine; a bypass pipe and abypass valve are mounted to the water inlet and water outlet of theengine to compensate the water inlet pressure with the water outletpressure, so as to further reduce the difference between water inletpressure and water outlet pressure and increase water inflow rate andwater outflow rate; thus, the system provided in the present inventionattains the purpose of simulating the actual operating condition ofengine in the vehicle for the cooling water system in the engine test.The system provided in the invention can keep the engine operatingstably at 100° C. boiling point, and can increase the water inletpressure by 20˜50 kPa.

Of course, many other embodiments can be implemented on the basis of thepresent invention. Those skilled in the art can make variousmodifications and variations to the embodiments, without departing fromthe spirit of the present invention. However, these modifications andvariations shall fall into the protected scope of the present inventionas confined by the claims.

1. A coolant temperature control system for engine performance test,comprising an internal coolant circulation system, a heat exchange unit,a temperature monitoring and control unit, and an external coolantcirculation system, wherein, the internal coolant circulation system andthe external coolant circulation system are connected to the heatexchange unit respectively, and the internal coolant circulation systemis connected to the engine; the temperature monitoring and control unitis connected to the internal coolant circulation system, the heatexchange unit, and the external coolant circulation system;characterized in that, the internal coolant circulation system is aclosed internal circulation system provided with a bypass unit forreducing the difference between water inlet pressure and water outletpressure of the internal coolant circulation system, the bypass unitcomprises a bypass pipe and a bypass valve, the bypass valve is mountedon the bypass pipe, and the bypass pipe communicates the engine waterinlet pipe with the engine water outlet pipe.
 2. The coolant temperaturecontrol system according to claim 1, characterized in that, the closedinternal circulation system comprises the engine water outlet pipe, anexpansion water tank, a heat exchange pipe, the engine water inlet pipe,and the bypass unit, which are connected in sequence; the engine wateroutlet pipe is connected to the water outlet of the engine; the enginewater inlet pipe is connected to the water inlet of the engine; the heatexchange pipe is connected to the heat exchange unit.
 3. The coolanttemperature control system according to claim 2, characterized in that,the closed internal circulation system further comprises a vapor exhaustunit which comprises an extension pipe and an vapor exhaust pipe,wherein, one end of the extension pipe is connected to the top of theexpansion tank, and the other end of the extension pipe is provided witha valve; the vapor exhaust pipe connects a water channel in the cylinderhead of the engine to the extension pipe.
 4. The coolant temperaturecontrol system according to claim 1, characterized in that, thetemperature monitoring and control system comprises a temperature sensorand an electric temperature control box that are connected to eachother, wherein, the temperature sensor is mounted on the engine wateroutlet pipe, and the electric temperature control box is connected tothe heat exchange unit and the external coolant circulation system. 5.The coolant temperature control system according to claim 1,characterized in that, the heat exchange unit is a plate-type heatexchanger.
 6. The coolant temperature control system according to claim2, characterized in that, the heat exchange pipe is further providedwith a manual bleed valve and an automatic bleed valve.
 7. The coolanttemperature control system according to claim 1, characterized in that,the engine water inlet pipe is further provided with a waterreplenishing valve.
 8. The coolant temperature control system accordingto claim 2, characterized in that, a coolant filter is further providedon the heat exchanger tube at the end near the expansion water tank. 9.The coolant temperature control system according to claim 2,characterized in that, a regulating valve is provided at the jointbetween the heat exchange pipe and the engine water inlet pipe.
 10. Thecoolant temperature control system according to claim 2, characterizedin that, a valve is provided at the joint between the engine wateroutlet pipe and the expansion water tank, and a valve is provided at thejoint between the heat exchange pipe and the engine water inlet pipe.